This invention relates generally to wheel and tire assemblies for automobiles and the like, and more particularly to a balancing device which is highly sensitive and accurate and yet simple in construction.
There are many known methods and devices for balancing wheel and tire assemblies. Each of these devices is adapted to locate the out of balance condition of the wheel and tire assembly by finding the heaviest section around the circumference of the assembly. Typically, a weight is added to the assembly at the lightest point in order to counter-balance the condition. Some of these known devices and methods incorporate suspending the wheel and tire assembly at the center hub to support the wheel at the hub on a support member. Various suspension methods and devices are known as well as various supporting devices.
For example, U.S. Pat. No. 3,045,497, issued to Lackie, discloses a suspension or pendant wheel balancer having a cord extending through a cylinder. The cord suspends the cylinder in a fixed relation and the cylinder has a flange for supporting the tire and wheel assembly. A slip ring having a tapered external surface is used which slips over the cylinder and into the wheel hub opening for attempting to center the wheel relative to the cylinder. Use of such a tapered wedge design is known in the art for use as a centering device for a wheel balancer. However, it is also known that such a device is not highly accurate in centering the wheel because the wedge itself does not always completely level itself relative to the wheel. If the wedge or tapered devices cock sideways and is not level, the wheel will not be centered relative to the cylinder and therefore the balancing process loses accuracy.
U.S. Pat. No. 4,043,218, issued to Groeper, discloses a pendant wheel balancer also using a cord which suspends a support device. This balancer includes a cylinder having external threads for receiving a correspondingly threaded support member. The support member moves upward and downward relative to the cylinder in order to adjust the wheel support surface relative to the pivot between the cylinder and the cable. This device also includes a wheel centering mechanism including three cam elements which are independently adjustable in order to center the wheel. There is no accurate means provided for determining when the wheel is properly centered relative to the cylinder and therefore this device also provides inaccurate wheel balancing.
There are other suspension or a pendant wheel balancers known in the art as well. Each of these known devices typically includes one element either a centering means for accurately centering the wheel relative to a vertical axis or a sensitive element for finding the out of balance portion of the wheel. Some devices also include different types of pivot elements in order to provide a highly sensitive friction-free pivot so that the device may easily and accurately locate the out of balance of the wheel. However, none of these devices includes a means for accurately and precisely balancing a wheel which provides all three of these elements in a highly accurate, durable and inexpensive wheel balancer.